1. Field of the Invention
The present invention relates to data structures and processes for selecting and displaying information over a network between clients and servers. More particularly, but without limitation, the present invention relates to transferring data, as requested by a client from a server, efficiently through a communications link of given bandwidth.
2. Description of Related Art
Computer databases and the communications links between them have been compared to oceans connected by straws. That is, while computers (including clients and servers) can exchange much data through networks, the system designer should be cognizant that such links may be quickly overwhelmed. One approach to improve data exchange has been to increase the bandwidth available between clients and servers. Solutions include high-speed copper and fiber landlines, satellite transmission, and increasingly faster data switches.
However, no matter how wide the transmission band, the amount of data available to move is generally more massive than the capacity to move it. Moreover, blindly providing enough bandwidth to handle peak traffic is expensive and inefficient—at off-peak times the capability would be underutilized. A better solution is to balance bandwidth and data “resolution.” That is, a system can be designed to reasonably increase the available transmission bandwidth while intelligently selecting data of high interest and importance to send.
The prior art describes methods for transferring data of varying degrees of resolution through a network on an as requested or as required basis. For example, in Molloy, U.S. Pat. No. 6,078,349, a system is disclosed in which video data on a display screen is sent in high resolution only to the portion of the screen at which a viewer is looking. As the viewer scans another section of the screen, the system detects the eye movement and requests high-resolution video data for that section. Molloy, however, may be inefficient for packet switched networks such as the Internet; by the time a server receives new instructions and transmits data, the viewer may have lost interest and may have moved on to another section of the screen or a new screen entirely.
Therefore, there is a need for an alternate means for providing high-resolution images by an efficient use of the available bandwidth of a transmission medium.